Multilayer iron soleplate made up of co-laminated materials

ABSTRACT

An iron. The invention relates to a soleplate for an iron, the soleplate comprising a casting (1) secured to a metal ironing cover (4) made up of at least two layers of different materials, said soleplate being characterized in that the metal cover (4) is made up of an assembly comprising at least two layers (5, 6) of co-laminated materials, in which assembly the first layer (5) forms the layer for fixing to the casting (1) and is constituted by the same material as the casting (1) or by a material having similar physical characteristics, and the second layer (6) forms the ironing layer, the thickness of the second layer lying in the range 5% to 40% of the thickness of the first layer (5), and preferably in the range 15% to 17%. A soleplate for an iron.

TECHNICAL FIELD

The present invention relates to a soleplate for an iron, the soleplatecomprising a casting having a metal ironing cover fixed thereon byfixing means.

PRIOR ART

The casting of an iron is a part which is generally made of aluminum,and which has a metal cover mounted directly thereon to form the ironingsoleplate. It is already known that a stainless steel metal cover can bemounted on the aluminum casting and can be fixed by means of a siliconeadhesive. Fixing may be improved by clipping the periphery of the coveronto the soleplate. To make such an ironing soleplate, it is necessaryto machine some of the surfaces of the casting prior to fixing on themetal cover. As a result, making such an iron soleplate involves varioussteps that increase the final cost of the product. Furthermore, becauseof large differences between the coefficients of thermal expansion ofthe aluminum casting and of the stainless steel metal cover, thestrength and the structural integrity of the soleplate deteriorate overtime. This gives rise to play between the various layers, and toprogressively worsening heat transmission during the life of the iron.

Admittedly, alternatives or improvements, such as increasing therelative thickness of the stainless steel sheet, do indeed improve thestability of the soleplate over time to some extent, but they alsoreduce heat transfer, and clearly they also increase the cost of thefinished product.

Naturally, co-laminated materials are also well known, and they arealready used in particular in automobile construction. In that field,co-laminated materials of the two-layer aluminum-and-stainless steeltype are used because of the anti-corrosion properties of stainlesssteel and because of its pleasing appearance.

Aluminum-and-stainless steel type co-laminated materials are also usedto make the bottoms of some kinds of saucepans. Such materials are usedfor that purpose because of the heat diffusion provided by aluminum andbecause of the appearance provided by the outer layer of stainlesssteel, but no concern is given to the large difference between therespective coefficients of thermal expansion of those two co-laminatedmaterials, which difference gives rise to a well known effect wherebythe bottom of the saucepan bulges. Because of the methods of heatingthat are used, and in view of the relative unimportance of the heattransmission factor for such cooking utensils, this phenomenon wherebythe bottom of the saucepan bulges and the structure of its bottombecomes somewhat spoiled has always been accepted.

In order to make soleplates for irons, it is also known that layers ofdifferent metals can be assembled together by means of solid phasebonding. Such soleplates are described in Document FR-A-1 502 451 andthey are associated with an additional layer of "bonding" metal which isheated to its melting point so as to obtain metallurgical bonding whenthe casting of the iron is cast on the soleplate. Document FR-A-1 502451 also describes a method of making a soleplate for an iron and offixing it to the casting of the iron while said casting is being cast.Such a method suffers from significant drawbacks, e.g. the complexityand the cost of the means required to implement it.

DESCRIPTION OF THE INVENTION

An object of the present invention is to remedy the above-mentionedproblems encountered in making soleplates for irons, and to provide anovel soleplate which is simpler to make and which does not require anysurface preparation, while retaining good heat exchange properties andwithout any significant deformation.

Another object of the invention is to provide a soleplate for an iron,in which thermal expansion is accommodated so as to guarantee a longlife-span for the soleplate, as well as good quality ironing.

Another object of the invention is to provide an iron in which it isparticularly simple and cheap to fix the metal cover to the casting.

Another object of the invention is to provide a novel use forco-laminated materials in the field of household appliances, as well asa method of assembling together a casting and a metal ironing cover.

The invention achieves the above objects by providing a soleplate for aniron, the soleplate comprising a casting secured to a metal ironingcover made up of at least two layers of different materials, saidsoleplate being characterized in that the metal cover is made up of anassembly comprising at least two layers of co-laminated materials, inwhich assembly the first layer forms the layer for fixing to the castingand is constituted by the same material as the casting or by a materialhaving similar physical characteristics, and the second layer forms theironing layer, the thickness of the second layer lying in the range 5%to 40% of the thickness of the first layer, and preferably in the range15% to 17%.

The invention also achieves the objects by providing use of aco-laminated material based on at least two layers as a metal ironingcover for an iron.

The invention also achieves the above objects by providing a method ofmaking a soleplate for an iron, in which method a casting is secured toa metal ironing cover made up of at least two layers of differentmaterials, said method being characterized in that it consists in takinga metal cover made up of at least two layers of co-laminated materials,in mounting said cover on the already-formed casting, and in fixing itthereto by fixing means.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the invention will appear in moredetail on reading the following description given by way of non-limitingexample with reference to the accompanying drawing, in which:

FIG. 1 is a fragmentary cross-section view showing the structure of aniron soleplate of the invention;

FIG. 2 is a fragmentary top view of the tip of an iron soleplate of theinvention, showing one of the means of fixing said soleplate; and

FIG. 3 is a fragmentary cross-section view on line III--III of FIG. 2,showing the fixing means shown in FIG. 2.

MANNER OF PERFORMING THE INVENTION

The iron soleplate shown in FIG. 1 includes a casting 1 cast in onepiece, e.g. made of aluminum, and delimiting a substantially planebottom face 2. The top portion of the casting 1 defines a series ofcavities and channels which co-operate with a plate that closes thesteam chamber and with a thermal skirt (not shown in the figures) toform the various compartments and elements that are essential to a steamiron. In the embodiment shown in FIG. 1, the iron soleplate is designedfor a steam iron, and the casting 1 is provided with a series ofopenings 3 for that purpose, the openings communicating with a steamchamber (not shown in the figures). However, the invention may beapplied to a dry iron.

As shown in FIG. 1, the iron soleplate of the invention further includesa metal cover 4 made up of an assembly comprising at least two layers ofco-laminated materials. The metal cover 4 includes a first layer 5 whichforms the fixing layer for fixing to the bottom face 2 of the casting 1.The first layer 5 is substantially plane and it is constituted by amaterial that is identical or at least that has similar physicalcharacteristics to the material of the casting 1. The term "similarphysical characteristics" essentially refers to physical characteristicsrelating to its coefficient of thermal expansion and/or to its hardnessof the material and/or to its thermal conductivity. The co-laminatedmetal cover 4 also includes a second layer 6 whose outside face 6a formsthe ironing layer.

In a particularly advantageous variant embodiment, the casting is madeof aluminum, and the metal cover comprises a two-layer co-laminatedassembly in which the first layer 5 is also constituted by aluminum,while the second layer 6 is constituted by stainless steel. In anothervariant, the first layer 5 may be constituted by a material havingsimilar physical characteristics to aluminum, such as copper, and thesecond layer 6 may be constituted by copper, by nickel, or by titanium.

To accommodate the differences in thermal expansion between the firstlayer 5 and the second layer 6, it is particularly advantageous tomaintain a specific thickness ratio between said layers. For thatpurpose, the thickness of the second layer 6 lies in the range 5% to 40%of the thickness of the first layer 5, and preferably in the range 15%to 17%. Preferably, the thickness of the second layer lies firstly inthe range 5% to 12% of the thickness of the first layer 5 and secondlyin the range 14% to 40%, or else in the range 15% to 40%, or even in therange 15% to 20%. Naturally, other preferred ranges such as 20% to 40%or 30% to 40% may be considered.

In another particularly advantageous embodiment of the invention, thetotal thickness of the co-laminated metal cover 4 corresponding to thesum of the thicknesses of the first layer 5 and of the second layer 6lies in the range 1.6 mm to 2 mm, and preferably in the range 1.7 mm to1.9 mm. Advantageously, the thickness of the second layer 6 lies in therange 0.1 mm to 0.4 mm and preferably in the range 0.2 mm to 0.3 mm,while the thickness of the first layer 5 lies in the range 1.4 mm to 1.7mm, and preferably in the range 1.5 mm to 1.6 mm. The above-mentionedthickness ranges are particularly advantageous for a co-laminatedmaterial of the aluminum-and-stainless steel type.

In another variant embodiment, the metal cover 4 may be made up of threelayers of co-laminated materials, the first layer 5 being of aluminum orcopper, the second layer 6 being of copper or stainless steel, and theintermediate layer (not shown in the figures) being of aluminum, copper,or ordinary steel.

Metal covers made in this way are of the aluminum-steel-stainless steeltype, or preferably of the aluminum-copper-stainless steel type, or elseof the copper-aluminum-stainless steel type. Each of the relativethicknesses of the first layer 5 and of the second layer 6 represent inthe range 15% to 17% of the total thickness of the three-layer cover,with the intermediate layer representing in the range 66% to 70% of thetotal thickness. Naturally, when steel is used for an intermediatelayer, the type of steel used is chosen on the basis of its suitabilityfor improving the strength of the co-laminated assembly, and also on thebasis of its thermal conductivity and expansion properties.

The co-laminated metal cover 4 is mounted on the casting 1 and is thenfixed thereto by fixing means. The fixing means comprise a layer ofadhesive 10 that is preferably heat-resistant and/or that is based onpolymerized silicone adhesive, and that extends between the bottom face2 and the first layer 5.

When the iron soleplate is to be used in a steam iron, it is providedwith steam holes 11 which are crimped onto the casting 1 inside orifices3. In which case, the crimped material forms the fixing means which maybe additional to the layer of adhesive 10.

To supplement fixing of the co-laminated metal cover 4, said cover mayoptionally be clipped mechanically to the casting 1 at at least onepoint. For that purpose, the metal cover 4 is provided with at least onezone forming a folded-over margin 12 which abuts via its edge against aperipheral border 13 of the casting 1. Because of the non-uniformity ofthe temperatures in the ironing soleplate, the folded-over margin 12 isprovided at the front of the soleplate, where the cover is subject tothe most stress, so as to constituted a clip-on tip (FIGS. 2 and 3).

In another variant embodiment of the invention, the entire perimeter ofthe metal cover 4 is provided with a rolled-over peripheral margin 14(FIG. 1) extending the second layer 6 and providing improved mechanicalstrength for the soleplate.

In an additional variant of the iron soleplate of the invention, themetal cover 4 is secured to the casting 1 by fixing means that areexclusively mechanical, e.g. constituted by bolts or by rivets. Acombination of various mechanical means may be considered, with orwithout a layer of adhesive 10 being used.

By using a co-laminated material based on at least two layers,preferably aluminum-stainless steel, as the metal ironing cover for aniron, it is possible to combine the advantages of both of theco-laminated metals. The first layer 5, constituted by a material thatis the same as or similar to the material of the casting, provides bothgood thermal conduction and also optimum adhesion and fixing, therebyimproving overall stability by means of the uniformity of the materials.The second layer 6 provides pleasing appearance and gives the soleplategood sliding properties without comprising the structural integrity ofthe co-laminated assembly despite the large differences in coefficientof thermal expansion, and the risks of deformation allowed for in thesoleplate as a whole. No shearing has been observed between thestainless steel and the aluminum, and, by making the casting of aluminumand the first layer 5 of aluminum as well, it is possible to omit anysurface-machining operations without observing any degradation inmechanical strength or any loss of heat transmission.

The thicknesses used also make it possible for the layers of theco-laminated assembly to expand differentially without giving rise toany mechanical deterioration in the structure of the soleplate. Inparticular, since the aluminum layer expands to a larger extent than thestainless steel layer, a small amount of tension is applied to thesurface of the stainless steel layer, thereby improving its slidingperformance.

The method of making an iron soleplate of the invention consists intaking a metal cover 4 made up of at least two layers of co-laminatedmaterials 5, 6, and in using fixing means 3, 10, 12 to fix said cover tothe casting 1 that has already been formed by using any known technique,e.g. by being cast in a mold. Since the casting 1 is in the form of asingle piece that is easy to transport, it can be secured to the metalcover 4 easily and it lends itself well to any industrial handling endassembly operations. The method of the invention also consists inmounting the metal ironing cover 4 on the casting 1 and then fixing itthereto without any surface preparation, since the fixing means 3, 10,12 are of the mechanical type. The method of the invention furtherconsists in using a co-laminated assembly based on at least two layersof materials having compositions and thicknesses as defined above, andin spreading a layer of heat-resistant adhesive on the surface of thefirst layer 5 that comes into contact with the casting 1, so as toconstitute the mechanical fixing means 3, 10, 12 at least in part.

POSSIBILITIES OF INDUSTRIAL EXPLOITATION

The invention can be applied to making iron soleplates, in particularsteam iron soleplates.

We claim:
 1. A soleplate for an iron, the soleplate comprising a casting(1) secured to a metal ironing cover (4) made up of at least two layersof different materials, said soleplate being characterized in that themetal cover (4) is made up of an assembly comprising at least two layers(5,6) of co-laminated materials, in which assembly the first layer (5)forms the layer for fixing to the casting (1) and is constituted by thesame material as the casting (1) or by a material having similarphysical characteristics, and the second layer (6) forms the ironinglayer, the thickness of the second layer lying in the range 5% to 40% ofthe thickness of the first layer (5).
 2. A soleplate according to claim1, characterized in that the total thickness of the first layer (5) andof the second layer (6) lies in the range 1.6 mm to 2 mm.
 3. A soleplateaccording to claim 2 wherein the total thickness of the first layer andof the second layer is in the range of 1.7 mm to 1.9 mm.
 4. A soleplateaccording to claim 1, characterized in that the thickness of the secondlayer (6) lies in the range 0.1 mm to 0.4 mm, and the thickness of thefirst layer (5) lies in the range 1.4 mm to 1.7 mm.
 5. A soleplateaccording to claim 4 wherein the thickness of the second layer is in therange 0.2 mm to 0.3 mm and the thickness of the first layer is in therange 1.5 mm to 1.6 mm.
 6. A soleplate claim 1 characterized in that themetal cover (4) consists of two layers (5, 6) of co-laminated materials.7. A soleplate according to claim 6, characterized in that the casting(1) is made of aluminum, the first layer (5) is constituted by amaterial from the following group; copper and aluminum, and the secondlayer (6) is constituted by a material from the following group: copper,nickel, titanium, and stainless steel.
 8. A soleplate according to claim1, characterized in that the metal cover (4) is mounted on a castingmade of aluminum, and is made up of three layers of co-laminatedmaterials, the first layer (5) being constituted by a material from thefollowing group: copper and aluminum, the second layer (6) beingconstituted by a material from the following group: stainless steel andcopper, and the intermediate layer being constituted by a material fromthe following group: aluminum, copper and steel.
 9. A soleplateaccording to claim 8, characterized in that each of the first and secondlayers (5, 6) represents in the range 15% to 17% of the total thicknessof the three-layer cover (4).
 10. A soleplate according to claim 1,characterized in that the casting (1) is secured to the metal cover (4)by fixing means which include a layer of adhesive (10).
 11. A soleplateaccording to claim 10 wherein the layer of adhesive is based on apolymerized silicone adhesive.
 12. A soleplate according to claim 1,characterized in that the metal cover is provided with a series ofopenings (3), said cover being crimped onto the casting (1) via saidopenings, whose crimped material forms fixing means.
 13. A soleplateaccording to claim 1, characterized in that the metal cover (4) includesat least one zone forming a folded-over margin (12) abutting against thecasting (1) and forming fixing means.
 14. A soleplate according to claim13 wherein said folded-over margin (12) is situated at the front of thesoleplate so as to constitute a clip-on tip.
 15. A soleplate accordingto claim 1 characterized in that the metal cover includes a rolled-overperipheral margin (14).
 16. An iron comprising a soleplate according toclaim
 1. 17. A soleplate according to claim 1 wherein the thickness ofthe second layer is in the range of 15% to 17% of the thickness of thefirst layer.
 18. A soleplate according to claim 1 wherein said castingis fabricated separately from said ironing cover and is secured to saidironing cover subsequent to fabrication of said casting.
 19. A method ofmaking a soleplate for an iron, in which method a casting (1) is securedto a metal ironing cover (4) made up of at least two layers of differentmaterials (5,6), said method being characterized in that it comprisestaking a metal cover (4) made up of at least two layers of co-laminatedmaterials (5,6), mounting said cover on the already-formed casting (1),and fixing the metal cover to the casting by fixing means (3,10,12). 20.A method according to claim 19, characterized in that it consists inmounting the metal ironing cover (4) on the casting (1) and in thenfixing it thereto without any surface preparation.
 21. A methodaccording to claim 19, characterized in that it consists in:using afirst layer (5) of the metal cover (4) as a fixing layer for fixing viamechanical-type fixing means (3, 10, 12); using the same material as thecasting (1) or a material having similar physical characteristics forsaid first layer (5); and using the second layer (6) to form the ironinglayer, the thickness of the second layer (6) lying in the range 5% to40% of the thickness of the first layer (5), and preferably in the range15% to 17%.
 22. A method according to claim 19, characterized in that itconsists in spreading a layer of heat-resistant adhesive on the surfaceof the first layer (5) that comes into contact with the casting (1) soas to constitute the fixing means (3, 10, 12) at least in part.